Below the Snake Pass, on the eastern side, the A57 crosses the Ladybower Reservoir on a long viaduct, and in a few seconds you go from bare moorland to a scene that looks almost Alpine: dark water fingering into wooded valleys, steep slopes of conifers, and the stone walls of the dams further up the valley. Ladybower and its neighbours, Derwent and Howden, form a chain of reservoirs in the Upper Derwent Valley that supply water to the cities of the East Midlands, and on a calm morning their surfaces reflect the hills perfectly.
The reservoirs have a story. Ladybower was built during the 1930s and 1940s, and its rising water drowned two villages, Ashopton and Derwent, whose people were moved to new homes. The church spire of Derwent stood above the water for a few years before it was demolished, and in dry summers, when the level drops, the foundations of old houses and walls still appear on the exposed mud. Further up the valley, the Derwent Dam, with its castle-like towers, was used by the RAF in 1943 to practise for the famous Dambusters raid on the dams of the Ruhr, because its shape resembled the German targets. There is a small museum in the dam's west tower, and every so often a commemorative flypast.
The other thing that catches people's eyes are the two great overflow shafts, known locally as the plugholes, which swallow water from the reservoir when it is full, a hypnotic sight after heavy rain. The roads around the reservoirs are popular with cyclists and walkers, and in summer the valley can be busy.
The A57 here is a good road, with sweeping bends, gentle gradients and a decent surface, and the views over the water are lovely. Traffic is moderate, heavier at weekends. To the south, the A6013 runs past the reservoir toward Bamford and the Hope Valley, a pleasant valley with villages, pubs and the ruined Peveril Castle above Castleton, which also has caves you can explore underground.
Hathersage and Bamford, a few kilometres south, have shops, cafes and pubs, and Hathersage has fuel. Sheffield, about twenty kilometres east, is the nearest big city. There is a visitor centre at Fairholmes, up the valley beside the Derwent Dam, with a cafe and toilets, which is worth a halt.